Why is the Electoral College important?

What does this answer mean?

The Electoral College is important because it decides who is elected president. USCIS also accepts a second answer: it provides a compromise between the popular election of the president and selection by Congress.

When people vote for president, they are choosing electors from their state. Each state gets as many electors as it has members of Congress, its senators plus its representatives, and the 23rd Amendment gives Washington, D.C., three. That makes 538 electors, and a candidate needs a majority, 270, to win.

The authors of the Constitution set up this system partly as a middle path between letting Congress choose the president and letting the people vote directly. Under the 12th Amendment, electors vote separately for president and vice president. If no candidate gets a majority, the House of Representatives chooses the president, with each state's delegation casting one vote.

At the interview, the shorter answer is "It decides who is elected president."